1. Field of Invention
The present invention is generally directed to vibration damping devices and, more particularly, to vibration damping devices which may be used in conjunction with golf clubs, baseball and softball bats, tennis rackets, hammers and other hand held devices which are designed to strike an object.
2. Description of the Related Art
There are many hand held devices which are used to strike objects. In the area of sports, for example, golf clubs, baseball and softball bats, and tennis rackets are used to strike golf balls, baseballs, softballs and tennis balls, respectively. Carpentry is another area where hand held devices are used to strike objects. Here, hammers and mallets are used to strike objects such as nails and dowels. Each device includes a striking surface which is used to strike to the object, a handle (or grip section) which is held by the user and connecting section extending therebetween. Golf clubs, for example, include a club head that is used to strike the golf ball. The club head is secured to one end of a shaft, while a grip is provided on the other.
In each of these devices, vibrations are transmitted from the striking surface, through the connecting section, and to the user's hands after impact. In almost every instance, the striking surface will include a so-called sweet spot. When the user strikes the object with the sweet spot, impact generated vibrations are minimized. Conversely, when the user fails to strike the object with the sweet spot, the impact generated vibrations can be quite unpleasant and can even cause pain and injury. Although skilled athletes, carpenters, etc. will typically strike an object with the sweet spot, novices and others of lesser skill will frequently fail to do so.
A number of vibration damping devices have been introduced in order to protect people from the unpleasant and sometimes injurious vibrations that result from failure to strike objects properly. By way of example, U.S. Pat. No. 5,294,119 to Vincent et al. discloses a vibration damping device that may be placed around the exterior surface of a golf club shaft or against the interior surface of a hollow shaft. The device includes a rigid tube and a layer of damping material which contacts either the interior surface or the exterior surface of the shaft. U.S. Pat. No. 5,362,046 to Sims discloses a more effective vibration damping device. The Sims device is a plug that is inserted into the butt end of a baseball bat, golf club shaft or other device. The plug consists primarily of a support, a stem extending from the support along the longitudinal axis thereof, and a damper secured to the free end of the stem. Oscillation of the stem and damper dissipates energy before it reaches the user's hands.